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Biomedical subjects

J Pettit

Publications and source records attributed to J Pettit.

12 recordsLinked to original sources
PubMed2001

By any other name: when will preschoolers produce several labels for a referent?

Two experiments investigated why preschool children sometimes produce multiple words for a referent (i.e. polynomy), but other times seem to allow only one word. In Experiment 1, 40 three- and four-year-olds completed a modification of Deák & Maratsos' (1998) naming task. Although social demands to produce multiple words were reduced, children produced, on average, more than two words per object. Number of words produced was predicted by receptive vocabulary. Lexical insight (i.e. knowing that a word refers to function or appearance) and metalexical beliefs (i.e. that a hypothetical referent has one label, or more than one) were not preconditions of polynomy. Polynomy was independent of bias to map novel words to unfamiliar referents. In Experiment 2, 40 three- and four-year-olds learned new words for nameable objects. Children showed a correction effect, yet produced more than two words per object. Children do not have a generalized one-word-per-object bias, even during word learning. Other explanations (e.g. contextual restriction of lexical access) are discussed.

Child Language↗
PubMed2001

Skeletal muscle acidosis correlates with the severity of blood volume loss during shock and resuscitation.

BACKGROUND: Continuous assessment of tissue perfusion and oxygen utilization may allow for early recognition and correction of hemorrhagic shock. We hypothesized that continuously monitoring skeletal muscle (SM) PO2, PCO2, and pH during shock would provide an easily accessible method for assessing the severity of blood loss and the efficacy of resuscitation. METHODS: Thirteen anesthetized pigs (25-35 kg) underwent laparotomy and femoral vessel cannulation. Multiparameter fiberoptic sensors were placed in the deltoid (SM) and femoral artery. Ventilation was maintained at a PaCO2 of 40-45 mm Hg. Total blood volume (TBV) was measured using an Evans blue dye technique. Animals were bled for 15 minutes, maintained at a mean arterial pressure (MAP) of 40 mm Hg for 1 hour, resuscitated (shed blood + 2 times shed volume in normal saline) and observed for 1 hour. Four animals served as controls (sham hemorrhage). Blood and tissue samples were taken at each time point. RESULTS: Blood loss ranged from 28.5-56% of TBV. SM pH and SM PO2 levels fell rapidly with shock. SM PO2 returned to normal with resuscitation; however, SM pH did not return to baseline. SM PCO2 significantly rose with shock, but returned to baseline promptly with resuscitation. There was a significant correlation between SM pH and blood volume loss at end shock (r2 = 0.73, p < 0.001) and recovery (r2 = 0.84, p < 0.001). Animals (n = 2) whose SM pH did not recover to 7.2 were found to have ongoing blood loss from biopsy sites and persistent tissue hypercarbia despite normal MAP. CONCLUSION: Continuous multiparameter monitoring of SM provides a minimally invasive method for assessing severity of shock and efficacy of resuscitation. Both PCO2 and PO2 levels change rapidly with shock and resuscitation. SM pH is directly proportional to lost blood volume. Persistent SM acidosis (pH < 7.2) and elevated PCO2 levels suggest incomplete resuscitation despite normalized hemodynamics.

Acidosis, Lactic↗
PubMed2001

Is a share buyback right for your company?

Contrary to popular wisdom, buybacks don't create value by raising earnings per share. But they do indeed create value, and in two very different ways. First, a buyback sends signals about the company's prospects to the market--hopefully, that prospects are so good that the best investment managers can make right now is in their own company. But investors won't see it that way if other, negative, signals are coming from the company, and it's rarely a good idea for companies in high-growth industries, where investors expect that money to be spent pursuing new opportunities. Second, when financed as a debt issue, a buyback is essentially an exchange of equity for debt, conferring the traditional benefits of leverage--a tax shield and a discipline for managers. For such a buyback to make sense, a company would need to have taxable profits in need of shielding, of course, and be able to predict its future cash flows fairly accurately. Justin Pettit has found that managers routinely underestimate how many shares they need to buy to send a credible signal to the markets, and he offers a way to calculate that number. He also goes through the iterative steps involved in working out how many shares must be purchased to reach a target level of debt. Then he takes a look at the advantages and disadvantages of the three most common ways that companies make the actual purchases--open-market purchases, fixed-price tender offers, and auction-based tender offers. When a company's performance is lagging, a share buyback can look attractive. Unfortunately, a buyback can backfire--unless executives understand why, when, and how to use this powerful and risky tool.

Capital Financing↗
PubMed1999

Bioelectrical impedance analysis in the evaluation of the nutritional status of continuous ambulatory peritoneal dialysis patients.

The authors evaluated the nutritional status of 47 continuous ambulatory peritoneal dialysis (CAPD) patients, 26 men (age 58.9 +/- 14.6 years, duration on CAPD 27.3 +/- 18.3 months) and 21 women (age 56.2 +/- 14.9 years, duration on CAPD 34.5 +/- 23.4 months), using subjective global assessment (SGA), an established method for the nutritional assessment of dialysis patients, and bioelectrical impedance analysis (BIA: body cell mass, fat mass, and phase angle). Of the studied patients, 19 were diabetic (age 59.7 +/- 13.8 years, duration on CAPD 29.2 +/- 19.7 months) and 28 were non diabetic (age 53.9 +/- 14.3 years, duration on CAPD 31.5 +/- 21.8 months. According to SGA, 24 patients were scored as well nourished (Group I), 18 as mildly malnourished (Group II), and 5 as moderately malnourished (Group III). No patient scored as severely malnourished (Group IV). Analysis of the main nutritional parameters for the subgroups revealed a proportional decrease in phase angle, with a statistically significant correlation (p < 0.009) between phase angle and SGA. No significant difference was seen in serum albumin levels between patients in Group I and Group II, but the mean level was significantly lower in patients in Group III compared to Group I. The nutritional and biochemical data in diabetic patients and non diabetic patients were not significantly different. BIA phase angle seems to be a simple and reliable method for the routine assessment of nutritional status in CAPD patients.

Diabetes Complications↗
PubMed1992

Effects of amino acid dialysate on appetite in CAPD patients.

The use of amino acid (AA) dialysate in CAPD patients may have theoretical disadvantages, since protein ingestion is known to suppress food intake in humans disproportionately to its energy value. Therefore we measured subjective appetite and food intake of CAPD patients in a cross-over study of 16 subjects (age 22-75 years, BMI 19-31, > 3 months on CAPD, non-diabetic and not protein malnourished). They received, in random order, either 4 weeks of dextrose only (their usual treatment), or one AA (1%) exchange replacing the first dextrose exchange each day. Subjective measurements of food intake (3 day food record) and quantitative measurements of lunch time food intake were obtained during a morning dextrose exchange after 28 days of each regimen. Except for a reduction in feelings of fullness during the AA treatment, there were no effects on feelings of hunger/satiety, food appeal, lunch-time food intake, or on 3-day food intake. We conclude that the use of a daily AA (1%) dialysate for 4 weeks does not affect subjective appetite or food intake of CAPD patients. There may even be a beneficial effect as the feeling of fullness decreased with the AA treatment.

Adult↗
PubMed1990

Six-month overnight intraperitoneal amino-acid infusion in continuous ambulatory peritoneal dialysis (CAPD) patients--no effect on nutritional status.

The long-term effect of an AA solution based on Travasol, a solution for total parenteral nutrition, given intraperitoneally over a 6-month period was studied in 5 patients 22 to 75 years old, having been on continuous ambulatory peritoneal dialysis (CAPD) for 3 to 57 months. A low oral protein intake (less than 0.8 g/kg bw/day) and/or a low serum albumin (less than 35 g/L) were used as inclusion criteria. Two liters of 1% AA solution were infused overnight, while a glucose Dianeal was used for the other exchanges. During the study, BUN increased from 22.04 mM/L to 28.06 mM/L the first month and remained at these levels, indicating the increased protein intake. However, average oral total energy and protein intake, body weight (bw), serum creatinine, cholesterol, triglycerides, total proteins, albumin, transferrin, skinfold thickness, total body potassium, and plasma AA levels remained basically unchanged. The average total body nitrogen decreased from 1.746 to 1.554 Kg, but this decrease did not reach statistical significance (p greater than 0.05). We conclude that intraperitoneal overnight administration of 2 L of 1% AA based on Travasol over 6 months did not improve the nutritional status of CAPD patients. This ineffectiveness might be due to the AA composition of the solution, the timing of administration, or to a low caloric intake and/or that our patients were not severely malnourished.

Amino Acids↗
PubMed1988

Use of lymphoscintigraphy in chyluria.

The roentgenographic procedure of choice in delineating lymphatic channels has been lymphangiography. Recently, radionuclide lymphoscintigraphy has been used to outline lymphatics in patients with various lymphatic disorders. We present and compare the results of lymphangiography and lymphoscintigraphy in 2 patients with chyluria. Since the results of lymphoscintigraphy correlated with lymphangiography, the application of this less invasive technique in the diagnosis and management of chyluria may be warranted.

Adult↗
PubMed1987

Reconstruction of penile agenesis by a posterior sagittal approach.

Penile agenesis is a rare condition requiring gender reassignment and staged perineal reconstruction. This report describes two children reconstructed by taking advantage of the posterior sagittal approach. This approach allows a precise anatomic dissection, construction of a neovagina and accurate positioning of all perineal orifices. We think that this is the preferred approach for this rare condition.

Disorders of Sex Development↗
PubMedDate not supplied

Isolation and experimental chicken-embryo-inoculation studies with budgerigar papovavirus.

Attempts to isolate and identify budgerigar papovavirus (BPV) were made during three separate outbreaks of disease diagnosed on pathological grounds. Direct electron microscopy was successful only when large areas of skin were extensively disrupted to release virus and then extracted with fluorocarbon to remove lipids. Direct inoculation of budgerigar tissue suspensions into chicken embryos or chicken cell cultures failed to produce detectable virus. However, when primary cultures of liver and kidney were prepared from affected budgerigars, BPV could be detected by electron microscopy and by the production of a cytopathic effect at the third or fourth passage in cell cultures. The isolated virus was pathogenic for 10-day-old but not 11- or 12-day-old chicken embryos. Inoculated 11- and 12-day-old embryos produced antibodies to BPV that were detectable 2 weeks after hatching by agar-gel-immunodiffusion tests.

Animals↗